Bank subsidiary (Details 10) (Class of financing receivables, USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2012	Dec. 31, 2011
Recorded investment:
With no related allowance recorded	$ 35,261	$ 35,261	$ 105,811
With an allowance recorded	32,137	32,137	17,878
Recorded investment	67,398	67,398	123,689
Unpaid principal balance:
With no related allowance recorded	46,964	46,964	124,300
With an allowance recorded	35,495	35,495	17,938
Unpaid principal balance	82,459	82,459	142,238
Related Allowance	4,621	4,621	3,704
Average recorded investment:
With no related allowance recorded	47,367	83,173	110,109
With an allowance recorded	22,199	17,516	19,816
Average recorded investment	69,566	100,689	129,925
Interest income recognized:
With no related allowance recorded	386	2,462	5,726
With an allowance recorded	182	641	1,541
Interest income recognized	568	3,103	7,267
Residential 1-4 family
Recorded investment:
With no related allowance recorded	15,963	15,963	19,217
With an allowance recorded	4,504	4,504	3,525
Recorded investment	20,467	20,467	22,742
Unpaid principal balance:
With no related allowance recorded	22,127	22,127	26,614
With an allowance recorded	4,504	4,504	3,525
Unpaid principal balance	26,631	26,631	30,139
Related Allowance	324	324	203
Average recorded investment:
With no related allowance recorded	15,919	17,104	21,385
With an allowance recorded	4,509	4,072	3,527
Average recorded investment	20,428	21,176	24,912
Interest income recognized:
With no related allowance recorded	57	225	282
With an allowance recorded	58	192	201
Interest income recognized	115	417	483
Commercial real estate
Recorded investment:
With no related allowance recorded			13,397
With an allowance recorded	2,929	2,929
Recorded investment	2,929	2,929	13,397
Unpaid principal balance:
With no related allowance recorded			13,397
With an allowance recorded	2,929	2,929
Unpaid principal balance	2,929	2,929	13,397
Related Allowance	7	7
Average recorded investment:
With no related allowance recorded	2,003	9,504	13,404
With an allowance recorded	976	326
Average recorded investment	2,979	9,830	13,404
Interest income recognized:
With no related allowance recorded		237	747
Interest income recognized		237	747
Home equity line of credit
Recorded investment:
With no related allowance recorded	584	584	711
With an allowance recorded	313	313
Recorded investment	897	897	711
Unpaid principal balance:
With no related allowance recorded	1,376	1,376	1,612
With an allowance recorded	421	421
Unpaid principal balance	1,797	1,797	1,612
Related Allowance	313	313
Average recorded investment:
With no related allowance recorded	630	648	954
With an allowance recorded	104	35
Average recorded investment	734	683	954
Interest income recognized:
With no related allowance recorded		1	6
Interest income recognized		1	6
Residential land
Recorded investment:
With no related allowance recorded	18,107	18,107	30,781
With an allowance recorded	7,021	7,021	7,792
Recorded investment	25,128	25,128	38,573
Unpaid principal balance:
With no related allowance recorded	22,854	22,854	39,136
With an allowance recorded	7,243	7,243	7,852
Unpaid principal balance	30,097	30,097	46,988
Related Allowance	2,321	2,321	2,525
Average recorded investment:
With no related allowance recorded	19,876	24,184	33,398
With an allowance recorded	7,134	7,306	8,158
Average recorded investment	27,010	31,490	41,556
Interest income recognized:
With no related allowance recorded	296	1,020	1,779
With an allowance recorded	122	429	603
Interest income recognized	418	1,449	2,382
Commercial loans
Recorded investment:
With no related allowance recorded	585	585	41,680
With an allowance recorded	17,370	17,370	6,561
Recorded investment	17,955	17,955	48,241
Unpaid principal balance:
With no related allowance recorded	585	585	43,516
With an allowance recorded	20,398	20,398	6,561
Unpaid principal balance	20,983	20,983	50,077
Related Allowance	1,656	1,656	976
Average recorded investment:
With no related allowance recorded	8,916	31,710	40,952
With an allowance recorded	9,476	5,777	8,131
Average recorded investment	18,392	37,487	49,083
Interest income recognized:
With no related allowance recorded	33	979	2,912
With an allowance recorded	2	20	737
Interest income recognized	35	999	3,649
Consumer loans
Recorded investment:
With no related allowance recorded	22	22	25
Recorded investment	22	22	25
Unpaid principal balance:
With no related allowance recorded	22	22	25
Unpaid principal balance	22	22	25
Average recorded investment:
With no related allowance recorded	23	23	16
Average recorded investment	$ 23	$ 23	$ 16